ORGANIC PETROLOGY CHARACTERS OF JURASSIC SOURCE ROCKS IN THE NORTHERN MARGIN OF QAIDAM BASIN

there are various organic macerals with different modalities,styles,genesises and optical features existing in Jurassic source rocks in the northern margin of Qaidam basin.They have different chemical compositions and constructions,different parent material styles and potential of forming hydrocarbons.The organic macerals in source rocks mainly include vitrinite,inertinite,exinite,sapropel and mineral pitch base.The main oil-generating components are exinite and sapropel,while the plentiful vitrinite (with the exception of clarovitrinite)and inertinite mainly generate gas.Dark-colored mudstone is mainly composed of minerals.Coal is mainly composed of organic macerals.Shale,oil shale and carbargilite are between both of the above.In all source rocks,shale and oil shale have the largest amounts of component with abundant hydrogen and sapropel macerals have absolute predominance.The main oil-forming components in shale and oil shale are bituminite and mineral pitch base,then stratiform alginate.Dark-colored mudstone has relatively less amount of component with abundant hydrogen.The main oil-forming components in it are stratiform alginate,sporinite and keratose,then mineral pitch base and exinite.The main oil-generating components in coal are relatively low content of keratose and sporinite.Rosin and exinite are in the next place.The main oil-forming components in carbargilite are sporinite,keratose and stratiform alginate.